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2025-07-15rust: types: add Opaque::cast_fromAlice Ryhl
Since commit b20fbbc08a36 ("rust: check type of `$ptr` in `container_of!`") we have enforced that the field pointer passed to container_of! must match the declared field. This caused mismatches when using a pointer to bindings::x for fields of type Opaque<bindings::x>. This situation encourages the user to simply pass field.cast() to the container_of! macro, but this is not great because you might accidentally pass a *mut bindings::y when the field type is Opaque<bindings::x>, which would be wrong. To help catch this kind of mistake, add a new Opaque::cast_from that wraps a raw pointer in Opaque without changing the inner type. Also update the docs to reflect this as well as some existing users. Signed-off-by: Alice Ryhl <aliceryhl@google.com> Acked-by: Andreas Hindborg <a.hindborg@kernel.org> Acked-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Danilo Krummrich <dakr@kernel.org> Acked-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20250624-opaque-from-raw-v2-1-e4da40bdc59c@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-06-22rust: enable `clippy::as_underscore` lintTamir Duberstein
In Rust 1.63.0, Clippy introduced the `as_underscore` lint [1]: > The conversion might include lossy conversion or a dangerous cast that > might go undetected due to the type being inferred. > > The lint is allowed by default as using `_` is less wordy than always > specifying the type. Always specifying the type is especially helpful in function call contexts where the inferred type may change at a distance. Specifying the type also allows Clippy to spot more cases of `useless_conversion`. The primary downside is the need to specify the type in trivial getters. There are 4 such functions: 3 have become slightly less ergonomic, 1 was revealed to be a `useless_conversion`. While this doesn't eliminate unchecked `as` conversions, it makes such conversions easier to scrutinize. It also has the slight benefit of removing a degree of freedom on which to bikeshed. Thus apply the changes and enable the lint -- no functional change intended. Link: https://rust-lang.github.io/rust-clippy/master/index.html#as_underscore [1] Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Tamir Duberstein <tamird@gmail.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-4-f43b024581e8@gmail.com [ Changed `isize` to `c_long`. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-06-22rust: enable `clippy::ptr_cast_constness` lintTamir Duberstein
In Rust 1.72.0, Clippy introduced the `ptr_cast_constness` lint [1]: > Though `as` casts between raw pointers are not terrible, > `pointer::cast_mut` and `pointer::cast_const` are safer because they > cannot accidentally cast the pointer to another type. There are only 3 affected sites: - `*mut T as *const U as *mut U` becomes `(*mut T).cast()`. - `&self as *const Self as *mut Self` becomes `core::ptr::from_ref(self).cast_mut()`. - `*const T as *mut _` becommes `(*const T).cast_mut()`. Apply these changes and enable the lint -- no functional change intended. Link: https://rust-lang.github.io/rust-clippy/master/index.html#ptr_cast_constness [1] Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Tamir Duberstein <tamird@gmail.com> Acked-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-2-f43b024581e8@gmail.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-06-04Merge tag 'rust-6.16' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux Pull Rust updates from Miguel Ojeda: "Toolchain and infrastructure: - KUnit '#[test]'s: - Support KUnit-mapped 'assert!' macros. The support that landed last cycle was very basic, and the 'assert!' macros panicked since they were the standard library ones. Now, they are mapped to the KUnit ones in a similar way to how is done for doctests, reusing the infrastructure there. With this, a failing test like: #[test] fn my_first_test() { assert_eq!(42, 43); } will report: # my_first_test: ASSERTION FAILED at rust/kernel/lib.rs:251 Expected 42 == 43 to be true, but is false # my_first_test.speed: normal not ok 1 my_first_test - Support tests with checked 'Result' return types. The return value of test functions that return a 'Result' will be checked, thus one can now easily catch errors when e.g. using the '?' operator in tests. With this, a failing test like: #[test] fn my_test() -> Result { f()?; Ok(()) } will report: # my_test: ASSERTION FAILED at rust/kernel/lib.rs:321 Expected is_test_result_ok(my_test()) to be true, but is false # my_test.speed: normal not ok 1 my_test - Add 'kunit_tests' to the prelude. - Clarify the remaining language unstable features in use. - Compile 'core' with edition 2024 for Rust >= 1.87. - Workaround 'bindgen' issue with forward references to 'enum' types. - objtool: relax slice condition to cover more 'noreturn' functions. - Use absolute paths in macros referencing 'core' and 'kernel' crates. - Skip '-mno-fdpic' flag for bindgen in GCC 32-bit arm builds. - Clean some 'doc_markdown' lint hits -- we may enable it later on. 'kernel' crate: - 'alloc' module: - 'Box': support for type coercion, e.g. 'Box<T>' to 'Box<dyn U>' if 'T' implements 'U'. - 'Vec': implement new methods (prerequisites for nova-core and binder): 'truncate', 'resize', 'clear', 'pop', 'push_within_capacity' (with new error type 'PushError'), 'drain_all', 'retain', 'remove' (with new error type 'RemoveError'), insert_within_capacity' (with new error type 'InsertError'). In addition, simplify 'push' using 'spare_capacity_mut', split 'set_len' into 'inc_len' and 'dec_len', add type invariant 'len <= capacity' and simplify 'truncate' using 'dec_len'. - 'time' module: - Morph the Rust hrtimer subsystem into the Rust timekeeping subsystem, covering delay, sleep, timekeeping, timers. This new subsystem has all the relevant timekeeping C maintainers listed in the entry. - Replace 'Ktime' with 'Delta' and 'Instant' types to represent a duration of time and a point in time. - Temporarily add 'Ktime' to 'hrtimer' module to allow 'hrtimer' to delay converting to 'Instant' and 'Delta'. - 'xarray' module: - Add a Rust abstraction for the 'xarray' data structure. This abstraction allows Rust code to leverage the 'xarray' to store types that implement 'ForeignOwnable'. This support is a dependency for memory backing feature of the Rust null block driver, which is waiting to be merged. - Set up an entry in 'MAINTAINERS' for the XArray Rust support. Patches will go to the new Rust XArray tree and then via the Rust subsystem tree for now. - Allow 'ForeignOwnable' to carry information about the pointed-to type. This helps asserting alignment requirements for the pointer passed to the foreign language. - 'container_of!': retain pointer mut-ness and add a compile-time check of the type of the first parameter ('$field_ptr'). - Support optional message in 'static_assert!'. - Add C FFI types (e.g. 'c_int') to the prelude. - 'str' module: simplify KUnit tests 'format!' macro, convert 'rusttest' tests into KUnit, take advantage of the '-> Result' support in KUnit '#[test]'s. - 'list' module: add examples for 'List', fix path of 'assert_pinned!' (so far unused macro rule). - 'workqueue' module: remove 'HasWork::OFFSET'. - 'page' module: add 'inline' attribute. 'macros' crate: - 'module' macro: place 'cleanup_module()' in '.exit.text' section. 'pin-init' crate: - Add 'Wrapper<T>' trait for creating pin-initializers for wrapper structs with a structurally pinned value such as 'UnsafeCell<T>' or 'MaybeUninit<T>'. - Add 'MaybeZeroable' derive macro to try to derive 'Zeroable', but not error if not all fields implement it. This is needed to derive 'Zeroable' for all bindgen-generated structs. - Add 'unsafe fn cast_[pin_]init()' functions to unsafely change the initialized type of an initializer. These are utilized by the 'Wrapper<T>' implementations. - Add support for visibility in 'Zeroable' derive macro. - Add support for 'union's in 'Zeroable' derive macro. - Upstream dev news: streamline CI, fix some bugs. Add new workflows to check if the user-space version and the one in the kernel tree have diverged. Use the issues tab [1] to track them, which should help folks report and diagnose issues w.r.t. 'pin-init' better. [1] https://github.com/rust-for-linux/pin-init/issues Documentation: - Testing: add docs on the new KUnit '#[test]' tests. - Coding guidelines: explain that '///' vs. '//' applies to private items too. Add section on C FFI types. - Quick Start guide: update Ubuntu instructions and split them into "25.04" and "24.04 LTS and older". And a few other cleanups and improvements" * tag 'rust-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (78 commits) rust: list: Fix typo `much` in arc.rs rust: check type of `$ptr` in `container_of!` rust: workqueue: remove HasWork::OFFSET rust: retain pointer mut-ness in `container_of!` Documentation: rust: testing: add docs on the new KUnit `#[test]` tests Documentation: rust: rename `#[test]`s to "`rusttest` host tests" rust: str: take advantage of the `-> Result` support in KUnit `#[test]`'s rust: str: simplify KUnit tests `format!` macro rust: str: convert `rusttest` tests into KUnit rust: add `kunit_tests` to the prelude rust: kunit: support checked `-> Result`s in KUnit `#[test]`s rust: kunit: support KUnit-mapped `assert!` macros in `#[test]`s rust: make section names plural rust: list: fix path of `assert_pinned!` rust: compile libcore with edition 2024 for 1.87+ rust: dma: add missing Markdown code span rust: task: add missing Markdown code spans and intra-doc links rust: pci: fix docs related to missing Markdown code spans rust: alloc: add missing Markdown code span rust: alloc: add missing Markdown code spans ...
2025-04-28rust: drm: gem: Add GEM object abstractionAsahi Lina
DRM GEM is the DRM memory management subsystem used by most modern drivers; add a Rust abstraction for DRM GEM. This includes the BaseObject trait, which contains operations shared by all GEM object classes. Signed-off-by: Asahi Lina <lina@asahilina.net> Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io> Reviewed-by: Lyude Paul <lyude@redhat.com> Link: https://lore.kernel.org/r/20250410235546.43736-8-dakr@kernel.org [ Rework of GEM object abstractions * switch to the Opaque<T> type * fix (mutable) references to struct drm_gem_object (which in this context is UB) * drop all custom reference types in favor of AlwaysRefCounted * bunch of minor changes and simplifications (e.g. IntoGEMObject trait) * write and fix safety and invariant comments * remove necessity for and convert 'as' casts * original source archive: https://archive.is/dD5SL - Danilo ] [ Fix missing CONFIG_DRM guards in rust/helpers/drm.c. - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-04-24rust: drm: file: Add File abstractionAsahi Lina
A DRM File is the DRM counterpart to a kernel file structure, representing an open DRM file descriptor. Add a Rust abstraction to allow drivers to implement their own File types that implement the DriverFile trait. Reviewed-by: Maxime Ripard <mripard@kernel.org> Signed-off-by: Asahi Lina <lina@asahilina.net> Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io> Reviewed-by: Lyude Paul <lyude@redhat.com> Link: https://lore.kernel.org/r/20250410235546.43736-7-dakr@kernel.org [ Rework of drm::File * switch to the Opaque<T> type * fix (mutable) references to struct drm_file (which in this context is UB) * restructure and rename functions to align with common kernel schemes * write and fix safety and invariant comments * remove necessity for and convert 'as' casts * original source archive: https://archive.is/GH8oy - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-04-24rust: drm: add device abstractionAsahi Lina
Implement the abstraction for a `struct drm_device`. A `drm::Device` creates a static const `struct drm_driver` filled with the data from the `drm::Driver` trait implementation of the actual driver creating the `drm::Device`. Reviewed-by: Maxime Ripard <mripard@kernel.org> Signed-off-by: Asahi Lina <lina@asahilina.net> Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io> Reviewed-by: Lyude Paul <lyude@redhat.com> Link: https://lore.kernel.org/r/20250410235546.43736-5-dakr@kernel.org [ Rewrite of drm::Device * full rewrite of the drm::Device abstraction using the subclassing pattern * original source archive: http://archive.today/5NxBo - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org>